A variety of storage systems used as data storage apparatuses in computer systems have been proposed. The storage systems range from small to large systems.
The storage system for a small computer system is provided as an apparatus with a minimum of features as a storage system, aiming at facilitating the introduction and reducing the cost at the time of initial introduction.
On the other hand, the storage system for a large computer system is adopting a different architecture from that for the small computer system. The large storage system is designed to have high expandability so it can respond to the needs of users who want to operate the largest system.
However, when the storage capacity needs increasing or the storage system needs scaling up due to integration with another storage system, the storage system for a small computer system may have to be replaced by a large storage system, or add another storage system.
In addition, the storage system for a large computer system, which has been designed from the outset to have high expandability, would place enormous cost pressures from the initial phase of introduction.